It sounds they talking about a wall watt meter, Kill-a-Watt is a known brand. Walmart should have something similar for 10-12 bucks. But it is really not neccessary!
A HLG-185H-1400 with four 36v COB's(Cree, BLX, Citizen) running full 1,4A has around 200w net. and 220w at the wall, maybe a tad more.
Turn the built-in dimmer counterclockwise until it stopped and you get around 50% out of the A version(100-110w). With the HLG-185H-C1400 "B" version you can dimm it down to 6-10% output via an external dimmer pot.
I would rather invest the 10-15 bucks in a cheap lux-meter(0-100.000lx) from e3ay/am4zon. This is much more useful to set the optimal brightness on canopy level. 15-25.000lx in veg and 30-50.000lx in bloom is a good point to start with. Optimum ambient temp range with LED's is 80-85°F/26-30°C and keep the humidity in check, 55-60% is neccessary at 85°F/30°C. Do not get closer than 24" at the beginning and then slowly decrease it to 12-16" in full bloom. If you see yellow streaks on the upper leaves, the distance is probably too small(intense level above 50klux) and you need to dimm the light down. Or the air is too dry, which cause a too high vapor pressure inside the leaves, the plants will transpire too much and therfor take up more nutriens, espechially calcium which locks out magnesium and iron. The result looks almost the same(mg. deficit). In this case rise the light a few inches or dimm it down until the symtomes dissapear.
I prefer rather little too much distance and less light than too little and therefor getting bleaching and other deficits. Slowly approach to the optimum, the maximum intensity is slightly different for each strain! An equatorial sativa strain can surely handle more light than a rudelalis or indika strain growing in the tundra.
If you follow these tips, you will most probably have a successful first LED indoor season.